JP5702238B2 - Drainage pipe and ground improvement method - Google Patents

Description

  The present invention relates to a sludge pipe and a ground improvement method used for horizontal jet stirring.

  In ground improvement by jet agitation, it is common to adjust the pressure in the ground by discharging mud while spraying the improved body, and to prevent bulging and the like on the ground surface.

For example, in ground improvement by horizontal jet agitation, mud at the time of pressure rise is performed by burying a mud pipe with a mud outlet above the jet pipe.
If the thing in which the some drainage port was formed is used as a mud pipe, the effort which arrange | positions a mud pipe with the movement of an improvement zone can be omitted.

  However, in the case of the conventional mud pipe, earth and sand may enter the mud pipe from the mud outlet when disposed in the ground. If soil or sand enters the drainage pipe, it may be blocked by the soil and become impossible to drain.

  As a construction method in which the inside is not blocked when installing the mud drain pipe in the ground, Patent Document 1 discloses that the mud pipe having a plurality of mud vents is buried in the ground with the mud vents closed. In addition, a ground improvement method is disclosed in which the mud outlet is opened during jet stirring.

Japanese Patent No. 2647572

In the ground improvement method of patent document 1, since all the mud openings are opened during jetting and stirring, mud may be discharged from unintended mud openings, and the ground can be improved with a desired shape and strength. There was a risk of disappearing.
Moreover, when the earth and sand at the drainage port other than the improved zone flows out or flows in, the discharged mud from the improved zone is inhibited, and there is a risk of poor drainage.

  From such a point of view, the present invention provides a drainage pipe and a ground improvement method capable of preventing the occurrence of poor waste mud and performing ground improvement by horizontal jet stirring with high quality. Let it be an issue.

In order to solve the above-mentioned problem, the mud pipe of the present invention has a plurality of first mud outlets formed in a row and an outer pipe whose tip is blocked, and a second mud outlet at the tip. An inner tube formed and inserted into the outer tube;
And a packer installed on the outer surface of the inner pipe behind the second mud outlet, wherein the packer has the second mud outlet at the frontmost part of the first mud. When positioned on the tip side of the mouth, the first packer positioned on the tip side of the first drainage port at the frontmost part and the rear of the first mudlet port on the rearmost part It is comprised by at least 2 with a 2nd packer, The clearance gap between the said outer tube and the said inner tube is obstruct | occluded by the said packer.

According to such a mud pipe, it becomes possible to prevent earth and sand from entering the inner pipe when the mud pipe is installed in the ground.
In addition, when the inner pipe is moved and the position of the second mud outlet is arranged at the first mud outlet near the improved zone, and the gap is closed by the packer, the first mud outlet near the improved zone is opened. In addition, unintentional inflow and outflow of earth and sand from the mud outlet can be prevented.

  If a packer is installed behind the first mud discharge port at the rearmost part and the gap between the outer pipe and the inner pipe is closed by the packer, the outer pipe and the inner pipe at the rear of the mud pipe It is possible to prevent soil and sand from entering the gap. Therefore, the movement of the inner pipe within the outer pipe is not hindered.

  The second mud discharge port may be formed on a front end surface of the inner pipe or may be formed on a side surface of the inner pipe.

  As long as the packer expands to closely contact the inner surface of the outer tube and the outer surface of the inner tube and closes the gap, the movement of the inner tube in the outer tube is not hindered by the packer. .

  Moreover, the ground improvement method of the present invention includes an arrangement step of arranging the injection pipe and the mud pipe in the ground, an improvement step of injecting the improved body from the injection pipe and discharging the mud through the drain pipe, A ground improvement method comprising: the drainage pipe having a plurality of first drainage ports and having an outer tube closed at the tip, a second mud discharge port at the tip and an inner portion of the outer tube. The inner pipe to be inserted, and a packer installed on the outer surface of the inner pipe behind the second mud outlet, and in the placement step, the front of the first mud outlet The packer is positioned, and the gap between the outer pipe and the inner pipe is closed by the packer. In the improvement step, the rear of the first mud outlet closest to the improvement zone where the jet agitation is performed by the injection pipe And positioning the packer on the packer It is characterized by closing the gap between more the inner pipe and the outer pipe.

  According to this ground improvement method, it is possible to prevent earth and sand from entering the mud pipe in the arrangement step. Moreover, it can also prevent that earth and sand enter into the 1st mud outlet which is not intended in the improvement process.

  In the arrangement step, if another packer is positioned behind the first mud discharge port at the rearmost part and the gap between the outer pipe and the inner pipe is closed by the packer, the outer pipe at the rear part of the mud pipe It is possible to prevent soil and sand from entering the gap between the inner pipe and the inner pipe.

  According to the drainage pipe and the ground improvement method of the present invention, it is possible to prevent poor drainage and to improve the ground by horizontal jet stirring with high quality.

(A)-(c) is sectional drawing which shows the drainage pipe which concerns on 1st embodiment. (A) is a longitudinal sectional view showing a drilling process according to the first embodiment, (b) is a sectional view enlarging a part of (a), (c) is a sectional view showing a process following (b). It is. (A) is a longitudinal sectional view showing a process following FIG. 2, (b) is a sectional view enlarging a part of (a), and (c) is a sectional view showing a process following (b). (A) is a longitudinal cross-sectional view which shows the process following FIG. 3, (b) is sectional drawing which shows an arrangement | positioning process, (c) is sectional drawing which shows the process following (b). (A) is the longitudinal cross-sectional view which shows the process following FIG. 5, (b) is sectional drawing to which a part of (a) was expanded. (A) is a longitudinal cross-sectional view which shows an injection process, (b) is sectional drawing to which a part of (a) was expanded. (A) And (b) is sectional drawing which shows the mud pipe which concerns on 2nd embodiment.

The first embodiment will be described.
As shown in FIG. 1A, the mud discharge pipe 1 of the present embodiment is configured by a double pipe structure including an outer pipe 10, an inner pipe 20, and a packer 30.

The outer tube 10 is closed at the tip. A plurality of first mud discharge ports 11, 11,... Are formed in rows on the side surface of the outer tube 10 at intervals along the axial direction.
Although this embodiment demonstrates the case where the 1st drain mud hole 11 is formed, the 1st mud hole 11 may be formed in multiple rows. Moreover, you may arrange | position the 1st mud outlets 11, 11, ... in a zigzag form by shifting the position of the 1st mud outlets 11, 11, ... formed in each row. The number of the first mud outlets 11 is not limited, and may be set as appropriate according to the length of the outer pipe 10, the range of ground improvement, and the like.

  Although the material of the outer tube 10 is not limited, in this embodiment, it is composed of a vinyl chloride tube.

The inner tube 20 is made of a tube material having an outer diameter smaller than the inner diameter of the outer tube 10 and is inserted into the outer tube 10.
The inner tube 20 is movable in the axial direction within the outer tube 10 (see FIG. 1B).

The front end surface of the inner pipe 20 is open and serves as a second mud discharge port 21.
Although the material of the inner pipe 20 is not limited, in this embodiment, it is comprised with a steel pipe.

The packer 30 is provided (installed) on the outer surface of the inner tube 20.
The packer 30 is comprised by the bag-shaped member made from resin, and expand | swells by inject | pouring a liquid or gas inside.

  When the packer 30 expands, the packer 30 comes into close contact with the inner surface of the outer tube 10 and the outer surface of the inner tube 20 and shields the gap S formed between the outer tube 10 and the inner tube 20.

  In the present embodiment, two packers 30 (first packer 31 and second packer 32) are fixed to the outer surface of the inner tube 20.

  The first packer 31 is installed behind the second mud outlet 21. That is, the first packer 31 is positioned on the distal end side of the first mud discharge port 11 in the frontmost portion in a state where the distal end of the inner tube 20 is positioned at the distal end portion of the outer tube 10.

  The second packer 32 is also in a state where the tip of the inner tube 20 is located at the tip of the outer tube 10 (a state where the first packer 31 is located on the tip side of the first mud discharge port 11). It is located behind the first first mud outlet 11.

In addition, the material, arrangement | positioning, quantity, etc. of the packer 30 are not limited, What is necessary is just to set suitably.
For example, in this embodiment, although the packer 30 is arrange | positioned so that the some 1st mud outlet 11,11, ... may be pinched | interposed from the front and back, the intermediate part of the some 1st mud outlet 11,11, ... The packer 30 may be disposed on the top.

Next, a ground improvement method using the mud pipe 1 will be described.
The ground improvement method of this embodiment includes a drilling step, an arrangement step, and an improvement step.

Drilling process, and drilling the ground G, is a process of forming a Haidorokan insertion holes h1 (see FIG. 4 (b)) and the injection pipe insertion hole h2 (see FIG. 3 (c)).

In the present embodiment, first, the injection pipe insertion hole h2 is formed.
The injection tube insertion hole h2 is formed by drilling the ground G through the drilling tube 41 by the drilling machine 40, as shown in FIG.

Although the material of the drill pipe 41 is not limited, a steel pipe is used in this embodiment.
The tip of the drill tube 41 is inclined and has a so-called bamboo split shape.

  As shown in FIG. 2B, the inside of the distal end portion of the hole drilling tube 41 is closed by the inner head 42.

  The inner head 42 is made of a steel member, shields the tip of the drilling tube 41, and prevents earth and sand from entering the drilling tube 41.

The tip of the inner head 42 is inclined in a so-called bamboo split shape according to the tip shape of the hole drilling tube 41.
A recovery rod 43 (see FIG. 2C) is connected to the rear end of the inner head. Although the structure of the connection part of the collection | recovery rod 43 is not limited, In this embodiment, it consists of a female screw.

When the drilling of the injection tube insertion hole h2 is completed, as shown in FIG. 2C, the recovery rod 43 is connected to the inner head 42 and the inner head 42 is moved with the drilling tube 41 remaining. to recover.
A male screw that is screwed into the female screw of the inner head 42 is formed at the tip of the recovery rod 43.

In the present embodiment, after the injection tube insertion hole h2 is drilled, the recovery rod 43 is inserted into the drill tube 41 and screwed to the inner head 42, and then the recovery rod 43 is pulled out, so that the inner head 42 is recovered.
The recovery rod 43 may be fixed to the inner head 42 in advance.

  When the inner head 42 is recovered, the guide tube 44 is inserted into the drilled tube 41 as shown in FIGS. 3 (a) and 3 (b).

  Although the material which comprises the guide pipe | tube 44 is not limited, In this embodiment, a vinyl chloride pipe | tube is used.

  When the guide tube 44 is disposed at a predetermined position, the drilled tube 41 is recovered as shown in FIG.

Next, the drainage pipe insertion hole h1 is drilled above the injection pipe insertion hole h2.
As shown in FIG. 4A, the drilling pipe insertion hole h1 is drilled by the drilling machine 40 through the drilling pipe 41.
In addition, what was used when drilling the injection pipe insertion hole h2 is used for the drilling machine 40 and the drilling pipe 41.

  When the hole drilling tube 41 is inserted to a predetermined position, the inner head 42 is recovered in a state where the hole drilling tube 41 is left (see FIG. 2C).

  An arrangement | positioning process is a process of arrange | positioning the sludge pipe 1 and the injection pipe 2 in the ground using the sludge pipe insertion hole h1 and the injection pipe insertion hole h2 which were formed in the drilling process.

First, as shown in FIG. 4B, the mud pipe 1 is inserted into the drill pipe 41.
At this time, the drainage pipe 1 is inserted in the state of FIG. That is, the second mud discharge port 21 of the inner pipe 20 is positioned on the front end side with respect to the first first mud discharge port 11, and the first packer 31 and the second packer 32 are expanded to close the gap S. Keep it. In this way, since the path from the first mud outlet 11 to the second mud outlet 21 is shielded by the first packer 31, earth and sand do not enter the inner pipe 20.

  In addition, even if earth and sand enter from the 1st mud outlet 11, since the clearance gap S is obstruct | occluded by the 2nd packer 32, earth and sand do not enter into back behind the 1st mud outlet 11 of the last part.

  When the mud drain pipe 1 is arranged at a predetermined position, the hole drilling pipe 41 is recovered as shown in FIG.

  Next, as shown in FIGS. 5A and 5B, the guide tube 44 is penetrated, and the injection tube 2 is disposed at a predetermined position.

  As shown in FIG. 6A, the improvement process is a process in which the improved body is injected from the injection pipe 2 to the improvement zone A and the mud pipe 1 discharges mud.

  First, as shown in FIG. 1B, the inner tube 20 is retracted in a state where the packer 30 is contracted, and the first packer 31 is positioned behind the first mud discharge port 11 closest to the improvement zone A. (See (c) in FIG. 1).

  Next, as shown in FIG. 1C, the first packer 31 and the second packer 32 positioned behind the first mud discharge port 11 are expanded. In this way, a mud path that communicates from the first mud port 11 to the second mud port 21 is secured, and the gap S (other path) between the outer tube 10 and the inner tube 20 is closed.

Subsequently, as shown in FIG. 6A, the improved body is injected from the injection pipe 2 into the improved zone A.
Moreover, the mud discharge by the mud pipe 1 is performed simultaneously with the injection of the improved body.

  In the improvement step, the improvement is performed while moving the improvement zone A at any time by moving the injection pipe 2 backward. As the improved zone A moves (retracting the injection pipe 2), as shown in FIG. 6B, the inner pipe 20 is also moved backward, and the mud is discharged from the first mud outlet 11 closest to the improved zone A. Do.

  According to the drainage pipe 1 and the ground improvement method of the present embodiment, the drainage pipe 1 (inner pipe 20) is not blocked, and it is possible to prevent poor drainage and to improve the ground by horizontal jet stirring. Can be performed with high quality.

Since the inner pipe 20 is moved and the position of the second mud discharge port 21 is arranged in the first mud discharge port 11 in the vicinity of the improved zone A and the gap is closed by the packer 30, the first in the vicinity of the improved zone A The mud outlet 11 can be opened and the unintentional inflow and outflow of earth and sand from the mud outlet 11 can be prevented.
Moreover, when installing the mud drain pipe 1 in the ground, it is prevented that earth and sand enter the inner pipe 20.

  By closing the gap between the outer pipe 10 and the inner pipe 20 behind the first first mud discharge port 11 by the second packer 32, the gap between the outer pipe 10 and the inner pipe 20 at the rear part of the mud pipe 1. It is prevented that the earth and sand enter into. Therefore, the movement of the inner tube 20 in the outer tube 10 is not hindered.

  Since the packer 30 is configured to be contractible, the movement of the inner tube 20 in the outer tube 10 is not hindered by the packer 30.

  By using the drilling machine and the drilling pipe used for drilling the injection pipe insertion hole h2 also for the drilling of the sludge pipe insertion hole h1, it is possible to reduce equipment costs and material costs.

Next, the mud pipe 1 according to the second embodiment will be described.
As shown in FIG. 7A, the mud discharge pipe 1 is configured by a double pipe structure including an outer pipe 10, an inner pipe 20, and a packer 30.

  Since the configuration of the outer tube 10 is the same as that shown in the first embodiment, a detailed description is omitted.

The inner tube 20 is made of a tube material having an outer diameter smaller than the inner diameter of the outer tube 10 and is inserted into the outer tube 10.
The inner tube 20 can move inside the outer tube 10 (see FIG. 1B).

A second mud discharge port 21 is formed on the side surface of the inner pipe 20.
Although the material of the inner pipe 20 is not limited, in this embodiment, it is comprised with a steel pipe.

The packer 30 is provided (installed) on the outer surface of the inner tube 20.
In the present embodiment, three packers 30 (a first packer 31, a second packer 32, and a third packer 33) are fixed to the outer surface of the inner tube 20.

  The first packer 31 is installed at the tip of the inner pipe 20 and behind the second mud discharge port 21. The first packer 31 is located on the distal end side of the first mud discharge port 11 in the foremost portion in a state where the distal end of the inner tube 20 is located at the distal end portion of the outer tube 10.

  The second packer 32 is also in a state where the tip of the inner tube 20 is located at the tip of the outer tube 10 (a state where the first packer 31 is located on the tip side of the first mud discharge port 11). It is located behind the first first mud outlet 11.

  The third packer 33 is installed on the tip side of the second mud discharge port 21 of the inner pipe 20. The third packer 33 may be disposed as necessary and may be omitted.

  Since the configuration of the other packer 30 is the same as the contents shown in the first embodiment, detailed description thereof is omitted.

  When ground improvement is performed using the mud pipe 1, the inner pipe 20 is first retracted with the packer 30 contracted. The inner pipe 20 is retracted until the first packer 31 is positioned behind the first mud outlet 11 closest to the improvement zone A (see FIG. 7B).

  Next, as shown in FIG. 7B, the first packer 31 and the third packer 33 positioned before and after the first mud outlet 11 are expanded. In this way, a mud path that communicates from the first mud port 11 to the second mud port 21 is secured, and the gap S (other path) between the outer tube 10 and the inner tube 20 is closed.

  Subsequently, the improved body is injected from the injection pipe 2 into the improved zone A, and at the same time, the mud discharged from the mud pipe 1 is performed.

  In addition, since each work procedure of the ground improvement method using the mud pipe 1 according to the other second embodiment is the same as the contents shown in the first embodiment, detailed description is omitted. .

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and the above-described constituent elements can be appropriately changed without departing from the spirit of the present invention.

For example, in each of the embodiments described above, the case where the second packer is arranged has been described, but the second packer 32 may be arranged as necessary and may be omitted.
In each of the above embodiments, the second packer is fixed to the outer surface of the inner tube, but the second packer may be fixed to the inner surface of the outer tube.

  Further, the configuration of the packer 30 is not limited as long as the gap S can be closed, and the packer 30 is not necessarily a bag-shaped member.

  In the embodiment, the injection pipe insertion hole is drilled first, but the drainage pipe insertion hole may be drilled first, or the injection pipe insertion hole and the drainage pipe insertion hole are simultaneously drilled. May be.

  In the above-described embodiment, the case where the guide tube is used when arranging the injection tube has been described. However, the injection tube may be arranged without using the guide tube.

  In the said embodiment, although the sludge pipe and the injection pipe were arrange | positioned in the ground using what is called universal boring, the arrangement | positioning method of a sludge pipe and a jet pipe is not limited to this. For example, horizontal boring may be performed using a shaft.

DESCRIPTION OF SYMBOLS 1 Mud pipe 2 Injection pipe 10 Outer pipe 11 1st mud outlet 20 Inner pipe 21 2nd mud outlet 30 Packer 31 1st packer 32 2nd packer A Improvement zone G Ground S Gap

Claims (7)

An outer pipe having a plurality of first mud outlets formed in a row and closed at the tip;
A second mud outlet is formed at the tip and an inner pipe inserted into the outer pipe;
A drainage pipe provided with a packer installed on the outer surface of the inner pipe at the rear of the second drainage port,
The packer, when the second mud discharge port is positioned on the front end side of the first mud discharge port of the foremost part, is positioned on the front end side of the first mud discharge port of the foremost part It is composed of at least two of a first packer and a second packer positioned behind the first drainage port at the rearmost part,
The mud discharge pipe, wherein a gap between the outer pipe and the inner pipe is closed by the packer. The waste mud according to claim 1, further comprising a packer installed behind the first drainage port at the rearmost portion, wherein the packer closes a gap between the outer tube and the inner tube. tube. The mud discharge pipe according to claim 1 or 2, wherein the second mud discharge port is formed on a front end surface of the inner pipe.   The said mud drain port is formed in the side surface of the said inner pipe, The mud pipe | tube of Claim 1 or Claim 2 characterized by the above-mentioned. The exhaust according to any one of claims 1 to 4, wherein the packer expands so as to closely contact the inner surface of the outer tube and the outer surface of the inner tube and close the gap. Mud pipe. An arrangement process of arranging the injection pipe and the drainage pipe in the ground;
An improved step of injecting the improved body from the injection pipe and discharging the mud by the exhaust pipe,
A ground improvement method comprising:
The mud pipe has a plurality of first mud outlets and an outer pipe whose tip is closed, an inner pipe having a second mud outlet at the tip and inserted into the outer pipe, and the second Having a packer installed on the outer surface of the inner pipe behind the mud outlet,
In the arranging step, the packer is positioned in front of the most advanced first drainage port, and the gap between the outer tube and the inner tube is closed by the packer,
In the improvement step, the packer is positioned behind the first drainage port closest to the improvement zone where the jet stirring is performed by the injection pipe, and the gap between the outer pipe and the inner pipe is closed by the packer. The ground improvement method characterized by doing. In the arrangement step, another packer is positioned behind the rearmost first drainage port, and the gap between the outer pipe and the inner pipe is closed by the packer. The ground improvement method described.

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